1. Field of the Invention
The present disclosure relates to an electric horn mounted in a vehicle such as a passenger car.
2. Description of the Related Art
There exists an electric horn that concentrically holds an exciting coil at a bottom of a closed-end tubular casing. The coil is formed by winding a wire around a coil bobbin with a tubular wire-wound portion. A fixed iron core is fixed into a tubular bore of the wire-wound portion of the coil bobbin. The fixed iron core is magnetized when the exciting coil is excited by a power supply. A diaphragm is fixed at an open end of the casing, and a movable iron core is provided at a shaft center of the diaphragm. The movable iron core and the fixed iron core are placed to face each other in an axial direction. A node contact breaker means is provided to the movable iron core in order to break a contact with a node member that is provided in a power supply circuit of the exciting coil. The movable iron core is suctioned from a position of a resting state (resting position) in which power is not supplied to the exciting coil toward a side of the fixed iron core under the magnetization of the fixed iron core by the power supply to the exciting coil. The node contact breaker means comes into contact (interferes) with the node member at a preset position to make the node member disconnected, which causes the fixed iron core to be demagnetized. The node member being disconnected, the movable iron core temporarily moves toward the fixed iron core under spring force of the diaphragm. When the movable iron core reaches a suction position that defines a maximum amplitude at the fixed iron core side, then the movable iron core moves away from the fixed iron core by spring force of the diaphragm. The node member stays disconnected by the node contact breaker until the movable iron core reaches a position to contact with the node member again. The movable iron core breaks a contact with the node member and makes the node member connected when the movable iron core moves away from the fixed iron core and arrives at a position to come into contact with the node member. Accordingly, the fixed iron core is magnetized by the node member, though the movable iron core temporarily moves away from the fixed iron core under spring force of the diaphragm. When the movable iron core arrives at a spaced position that define a maximum amplitude that is a farthest from the fixed iron core side, the movable iron core moves under suction (performs a suction movement) toward the fixed iron core in proximity by spring force of the diaphragm. The node member stays contacts by the node contact breaker means until the movable iron core reaches a position to contact with the node member again. This sort of conventional electric horn generates a warning sound when the movable iron core is axially displaced with a predetermined amplitude by repetition of the above described movements.
In particular, the movable iron core is configured to be axially displaced with the predetermined amplitude because opposing end surfaces of the fixed and movable iron cores in the axial direction are disposed to face the wire-wound portion of the coil bobbin of the exciting coil.
An example of the above-described electric horn is shown in Japanese Published Unexamined Patent Application No. JP-A-2001-287588.